Blown Wastegate Diaphram

[lucittm]

Fellow Turbo Wrenchers,
I opened my stock 964 turbo wastegate and found what is depicted in the picture below. Possibly an improper installation?

I think the diaphram is trashed because when I pull it back into shape, I can see light through the creasing.

No wonder my boost never seemed to taper off...

I cannot find a P/N for the diaphram. Anyone know what it is? Better yet, does anyone have one that I can buy? If you have an aftermarket WG (TiAL) maybe you could donate your old diaphram to a good cause...

Thanks,
Mark

[911nut]

I have a new, never used stock one, as well as an assortment of springs. Shoot me a PM.

[lucittm]

Here is a picture of the spring that was in my waste gate. Can anyone identify it? The PO said that he installed a stiffer than stock spring. He was not satisfied so he installed the next stiffer spring.

Could he have gone to 1 bar and then to 1.5 bar?

Thanks,
Mark

[911nut]

The stiffest spring I've ever seen for sale was a 1.2 bar spring. How long is that spring?

[lucittm]

The sping pictured above measures 6 7/8" overall. I wish I knew where it came from or who made it. The car records show that a 1 bar spring was installed at one point, but the PO told me the current spring was also an upgrade.

It seems very stiff. But I don't have much experience with these waste gates. I would guess it is 1.2 bar.

Thanks,
Mark

[911nut]

It's a 1 bar spring.

[lucittm]

911nut,
Thanks for the info on the spring. Now I know I have a 1 bar spring.

There were also two shims at the top of the spring. What would be the effect if I took one of them out? Or both of them? I was thinking about moving one of the shims to the bottom of the spring; I think mechanically it would be the same.

Thanks,
Mark

[beepbeep]

Originally Posted by lucittm

911nut,
Thanks for the info on the spring. Now I know I have a 1 bar spring.

There were also two shims at the top of the spring. What would be the effect if I took one of them out? Or both of them? I was thinking about moving one of the shims to the bottom of the spring; I think mechanically it would be the same.

Thanks,
Mark

Two extra shims on a 1 bar spring? Hmm...can it be that engine has air leaks and PO was trying to compensate with stiffer spring? I suggest fitting ordinary 0.7 spring, checking for leaks by pressurizing the intake path south of K-Jet first. If you lust for more boost, it's easily adjustable by fitting T-orifice bleed, Dawes device, Electronic boost controller or any other pneumatic device. This will also allow you to lower the boost back to 0.7 should need arise.

[A930Rocket]

The shims are there to make the spring stiffer and create higher boost. What you have to be careful of is the spring binding from too many or too thick of a shim(s).

I'd ditch the shims and use a 1 bar spring if you have the intercooleran, fuel, etc. to support it or get a .7 bar spring and use some sort of boost controller if you have the discipline not to go crazy high with it. I know I don't...

[911nut]

Originally Posted by A930Rocket

The shims are there to make the spring stiffer and create higher boost. What you have to be careful of is the spring binding from too many or too thick of a shim(s).

If the shims are real thin (like a spring washer) and look like doughnuts then they go on the top and bottom of the stock spring and there should only be two of them.

[WERK I]

Originally Posted by 911nut

if The Shims Are Real Thin (like A Spring Washer) And Look Like Doughnuts Then They Go On The Top And Bottom Of The Stock Spring And There Should Only Be Two Of Them.

+1

[rsrmike]

That is a 1.1 Bar spring from Andial.

I have one in the garage on the shelf if you would like a picture.. (make offer if anyone's interested, never used)

The shims are there to keep the spring from wearing a groove in the aluminum spring housing. Don't ditch them if they are any where near the thickness of your alternator shims.

Anything measurable with a ruler shouldn't be there Especially w/ a 1.1 bar spring

Good luck

[rsrmike]

[lucittm]

Mike,
Thanks for the spring ID. That confims the PO's story that he changed the spring twice. The first time it was probably the stock .7 to 1.0 and then to the Andial 1.1 bar spring.

The shims I have are very thin. I measured them at .50mm (.020"). They were both at the top of the spring. Clearly, someone has been in there and placed both shims where I found them.

I can't imagine that they would pre-load the spring very much. I like your explanation that they go on either end of the spring to protect the aluminum spring housing.

I have enclosed a picture of the shims below.

Thanks,
Mark

[911nut]

Originally Posted by lucittm

Mike,
Thanks for the spring ID. That confims the PO's story that he changed the spring twice. The first time it was probably the stock .7 to 1.0 and then to the Andial 1.1 bar spring.

1.0 to 1.1? Why did he bother with it?

[rsrmike]

Boost pipe...